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Finding the Fourth Proportional to 20.58, 28.40 and 13.29

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Solution

The fourth proportional to 20.58, 28.40 and 13.29 is: 18.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.58 : 28.40 = 13.29 : x
  2. Step 2: Convert to fraction form
    20.58/28.40 = 13.29/x
  3. Step 3: Cross multiply
    20.58x = 28.40 × 13.29
  4. Step 4: Simplify right side
    20.58x = 377.42
  5. Step 5: Solve for x
    x = 377.42/20.58
  6. Step 6: Final answer
    x = 18.34

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.